Kawasaki disease and sudden infant death syndrome: Any connection to vaccination?

Kawasaki disease (KD) and sudden infant death syndrome (SIDS) are two conditions with unknown etiology that occur in young children. KD is an acute self-limited vasculitis that occurs predominantly in infants and young children that can lead to coronary artery aneurysms or ectasia. Clinical criteria have been developed and well described to diagnose the constellation of signs and symptoms of this syndrome. Though 45 years have passed since the syndrome was first described, the etiology of KD remains elusive. It has been speculated that KD is infectious in origin, though no specific infectious source has been identified. Since KD presents at an age when infants and young children are receiving their primary vaccine series it has been questioned as to whether the vaccinations themselves are the inciting event behind KD. KD has been linked to a number of vaccines, yet no evidence of a cause-and-effect association exists and should not serve as a barrier to vaccination. SIDS is the unfortunate event when an infant under the age of 1 has an unexplained death. This phenomenon has been described since ancient times. Multiple risk factors have been identified and the greatest reduction in the SIDS rate occurred following the introduction of the American Academy of Pediatrics Back to Sleep campaign in 1994. Yet despite attempts to modify the known risk factors, approximately 7,000 deaths occur annually in the United States. The mechanism behind SIDS is not well established, but it has been hypothesized that both intrinsic and extrinsic events contribute to the infant death. As with KD, there has been an attempt to associate vaccine administration with SIDS. Multiple case-control studies, meta-analyses, and independent reviewers have found there to be no cause-and-effect association with vaccinations and SIDS, and that vaccines likely decrease the overall risk of SIDS.